One of the most intriguing parts of Paltrow and Falchuk's relationship is that Falchuk seemingly gets along with Paltrow's ex-husband, Chris Martin. Paltrow and Martin " consciously uncoupled" in 2014; together they have two kids, Apple and Moses.

In November, Paltrow publicly flaunted the positive relations between her ex and new fiance, posting an Instagram photo of Falchuk and Martin side by side, with the caption, "Sunday brunch #modernfamily."

A few days later, an anonymous source told People magazine that Falchuk and Martin had already met several times, and that "Chris accepted Brad a long time ago."

The source said, "It's amazing to see how the two families have come together with their kids." Falchuk is also divorced with two kids.

This, relationship experts say, is a wise — if unusual — move. Though neither expert I spoke to knows Paltrow personally and can't speak to what's right for her and her family, each shared some general thoughts on the situation.

"It does not happen a lot," said Hal Runkel, a marriage and family therapist. But "it absolutely is advisable." When you're co-parents, as Paltrow and Martin are, Runkel said, "you are still a family after the divorce."

On the other hand, exes who never had kids together don't necessarily have to stay connected. In fact, if you feel like you absolutely must introduce your ex to your new partner and you don't have kids together, Syrtash recommends asking yourself why. Runkel called it "totally unnecessary."

After a breakup without kids, Runkel said, "you're not trying to repair your past." Kids, on the other hand, are "about the present and the future."